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    <title>Network documentation</title>
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<h1>Network documentation</h1>

<table>
    <tr>
        <td>Author</td>
        <td>Jos de Jong, <a href="http://www.almende.com" target="_blank">Almende B.V.</a></td>
    </tr>
    <tr>
        <td>Webpage</td>
        <td><a href="http://almende.github.com/chap-links-library" target="_blank">Chap Links Library</a></td>
    </tr>
    <tr>
        <td>License</td>
        <td> <a href="http://www.apache.org/licenses/LICENSE-2.0" target="_blank">Apache License, Version 2.0</a></td>
    </tr>
</table>


<h2><a name="Contents"></a>Contents</h2>
<ul>
    <li><a href="#Overview">Overview</a></li>
    <li><a href="#Example">Example</a></li>
    <li><a href="#Loading">Loading</a></li>
    <li><a href="#Data_Format">Data Format</a></li>
    <li><a href="#Data_Import">Data Import</a></li>
    <li><a href="#Dynamic_Data">Dynamic Data</a></li>
    <li><a href="#Configuration_Options">Configuration Options</a></li>
    <li><a href="#Methods">Methods</a></li>
    <li><a href="#Events">Events</a></li>
    <li><a href="#Data_Policy">Data Policy</a></li>
</ul>

<h2><a name="Overview"></a>Overview</h2>
<p>
    Links Network is an interactive chart to visualize networks.
    It allows creating nodes, links between the nodes, and interactive packages
    moving between nodes.
    Interaction can be real time or can be animated from a set of historical data.
    The visualization supports custom styles, colors, sizes, images, and more.
</p>

<p>
    The network visualization works smooth on any modern browser for up to a
    few hundred nodes and connections.
</p>

<p>
    Network is developed as a Google Visualization Chart in javascript,
    but can also be used without the Google libraries.
    There is a GWT wrapper available to use the Network in GWT (Google Web Toolkit).

    It runs on all modern browsers without additional requirements.
    Network is tested on Firefox 3.6+, Safari 5.0+, Chrome 6.0+, Opera 10.6+,
    Internet Explorer 9+.
</p>

<p>
    To get started with Network, download
    <a href="http://almende.github.com/chap-links-library/downloads.html">network.zip</a>,
    and unzip the contents in a subfolder network on your site.

    Examples can be found in the
    <a href="../examples" target="_blank">examples</a> directory.

<h2><a name="Example"></a>Example</h2>
<p>
    Here a basic network example.
    More examples can be found in the
    <a href="../examples" target="_blank">examples directory</a>.
</p>

<div style="text-align:center;">
    <iframe src="example.html" style="border:none; width:420px; height:520px;"></iframe>
</div>
<pre class="prettyprint lang-html">&lt;!DOCTYPE HTML PUBLIC
    "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"&gt;
&lt;html&gt;
  &lt;head&gt;
    &lt;title&gt;Links Network demo&lt;/title&gt;

    &lt;style&gt;
      body {font: 10pt arial;}
    &lt;/style&gt;

    &lt;script type="text/javascript" src="http://www.google.com/jsapi"&gt;&lt;/script&gt;
    &lt;script type="text/javascript" src="../network.js"&gt;&lt;/script&gt;

    &lt;script type="text/javascript"&gt;
      google.load("visualization", "1");

      // Set callback to run when API is loaded
      google.setOnLoadCallback(drawVisualization);

      // Called when the Visualization API is loaded.
      function drawVisualization() {
        // Create a datatable for the nodes.
        var nodesTable = new google.visualization.DataTable();
        nodesTable.addColumn('number', 'id');
        nodesTable.addColumn('string', 'text');
        nodesTable.addColumn('string', 'style');  // optional
        nodesTable.addRow([1, "Office", "circle"]);
        nodesTable.addRow([2, "Main", "circle"]);
        nodesTable.addRow([3, "Server 1", "database"]);
        nodesTable.addRow([4, "Server 2", "database"]);
        nodesTable.addRow([5, "Internet", "circle"]);
        nodesTable.addRow([101, "Computer A", undefined]);
        nodesTable.addRow([102, "Computer B", undefined]);
        nodesTable.addRow([103, "Computer C", undefined]);
        nodesTable.addRow([104, "Computer D", undefined]);
        nodesTable.addRow([105, "Computer E", undefined]);

        // create a datatable for the links between the nodes
        var linksTable = new google.visualization.DataTable();
        linksTable.addColumn('number', 'from');
        linksTable.addColumn('number', 'to');
        linksTable.addColumn('number', 'width');  // optional
        linksTable.addRow([1, 101, undefined]);
        linksTable.addRow([1, 102, 2]);
        linksTable.addRow([1, 103, undefined]);
        linksTable.addRow([1, 104, undefined]);
        linksTable.addRow([1, 105, undefined]);
        linksTable.addRow([1, 2, 5]);
        linksTable.addRow([2, 3, 3]);
        linksTable.addRow([2, 5, 4]);
        linksTable.addRow([5, 4, 2]);

        // specify options
        var options = {
          width:  "400px",
          height: "500px",
          stabilize: false, // do not stabilize before displaying
        };

        // Instantiate our network object.
        var network = new links.Network(document.getElementById('mynetwork'));

        // Draw our network with the created data and options
        network.draw(nodesTable, linksTable, options);
      }
   &lt;/script&gt;
  &lt;/head&gt;

  &lt;body&gt;
    &lt;div id="mynetwork"&gt;&lt;/div&gt;
  &lt;/body&gt;
&lt;/html&gt;

</pre>


<h2><a name="Loading"></a>Loading</h2>

<p>
    The Network can be used with or without using Google Javascript libraries. The
    Google libraries provided classes such as DataTable, DataView, and eventlisteners.
    But the Google libraries cannot be used in an offline environment.
</p>

<p>
    Download the file
    <a href="http://almende.github.com/chap-links-library/downloads.html"><code>network.zip</code></a>,
    and unzip it in your html page such that the files are located in a subfolder network.
    Include the google API and the following files in the head of your html code:
</p>

<pre class="prettyprint lang-html">
&lt;script type="text/javascript" src="http://www.google.com/jsapi"&gt;&lt;/script&gt;
&lt;script type="text/javascript" src="network/network.js"&gt;&lt;/script&gt;
</pre>

<p>
    If you use the google visualization API needs to be loaded in order to use DataTable.
    If no Google visualization API is used, the network can be drawn after the
    page has been loaded.
</p>
<pre class="prettyprint lang-js">google.load("visualization", "1");
google.setOnLoadCallback(drawVisualization);
function drawVisualization() {
  // load data and create the network here
}
</pre>


The class name of the Network is <code>links.Network</code>
<pre class="prettyprint lang-js">var network = new links.Network(container);</pre>

After being loaded, the network can be drawn via the function <code>draw()</code>,
provided with data and options.
<pre class="prettyprint lang-js">network.draw(nodes, links, packages, options);</pre>
where <code>nodes</code>, <code>links</code>, and <code>packages</code> are
a <code>DataTable</code>, and <code>options</code> is a name-value map in the
JSON format. Both <code>links</code> and <code>packages</code> are optional.




<h2><a name="Data_Format"></a>Data Format</h2>
<p>
    Network requires two tables with three data tables:
</p>
<ul>
    <li><b>Nodes</b>. A table which defines the nodes.</li>
    <li><b>Links</b>. A table which defines links between nodes.</li>
    <li><b>Packages</b>. A table which defines static and/or interactive packages
        moving between nodes.</li>
</ul>
<p>
    The tables with Links and Packages are optional.

    The Timeline supports two data types for each of the tables: a Javascript Array
    or a Google DataTable.

    Note that the Google API is only available online and cannot be used in an
    offline environment.
</p>

<h3>Nodes</h3>

<p>
    The node table is required for the network visualization.

    The table must contain at least a column <code>id</code>.
    The table can have extra columns, used to define the type and style of
    individual nodes. Values in optional columns can be left <code>undefined</code>
    for individual nodes. In that case, the default value will be applied.
</p>

<p>
    A Google DataTable with nodes is constructed as:
</p>
<pre class="prettyprint lang-js">
var nodesTable = new google.visualization.DataTable();
nodesTable.addColumn('number', 'id');
nodesTable.addColumn('string', 'text');  // optional
// ... optionally add more columns

nodesTable.addRow([1, 'Node 1']);
// ... more data
</pre>

<p>
    A JavaScript Array with nodes is constructed as:
</p>
<pre class="prettyprint lang-js">
var nodesTable = [

];

nodesTable.push({
  'id': 1,
  'text': 'Node 1'
});
// ... more data
</pre>


<p>
    The data columns are defined as:
</p>

<table>
    <tr>
        <th>Name</th>
        <th>Type</th>
        <th>Required</th>
        <th>Description</th>
    </tr>

    <tr>
        <td>action</td>
        <td>string</td>
        <td>no</td>
        <td>By specifying <code>action</code>, a node can be created, updated,
            or deleted. This is useful in combination with <code>timestamp</code>
            to animate history, or for dynamically updating the network.

            Available values are: <code>create</code>,
            <code>update</code> (default), or <code>delete</code>.
        </td>
    </tr>

    <tr>
        <td>backgroundColor</td>
        <td>String</td>
        <td>"#97C2FC"</td>
        <td>Background color for the node.</td>
    </tr>

    <tr>
        <td>borderColor</td>
        <td>String</td>
        <td>"#2B7CE9"</td>
        <td>Border color for the node.</td>
    </tr>

    <tr>
        <td>group</td>
        <td>*</td>
        <td>no</td>
        <td>A group number or name. The type can be <code>number</code>,
            <code>string</code>, or an other type. All nodes with the same group get
            the same color schema.</td>
    </tr>

    <tr>
        <td>fontColor</td>
        <td>String</td>
        <td>"black"</td>
        <td>Font color for text in the node.</td>
    </tr>

    <tr>
        <td>fontFace</td>
        <td>String</td>
        <td>"sans"</td>
        <td>Font face for text in the node, for example "verdana" or "arial".</td>
    </tr>

    <tr>
        <td>fontSize</td>
        <td>Number</td>
        <td>14</td>
        <td>Font size in pixels for text in the node.</td>
    </tr>

    <tr>
        <td>highlightColor</td>
        <td>String</td>
        <td>"#D2E5FF"</td>
        <td>Background color of the node when selected.</td>
    </tr>

    <tr>
        <td>id</td>
        <td>*</td>
        <td>yes</td>
        <td>A unique id for this node.
            Nodes may not have duplicate id's.
            Id's do not need to be consecutive.
            An id is normally a number, but may be any type.</td>
    </tr>

    <tr>
        <td>image</td>
        <td>string</td>
        <td>no</td>
        <td>Url of an image. Only applicable when the style of the node is
            <code>image</code>.</td>
    </tr>

    <tr>
        <td>radius</td>
        <td>number</td>
        <td>no</td>
        <td>Radius for the node. Applicable for all styles except <code>rect</code>,
            <code>circle</code>, and <code>database</code>.
            The value of <code>radius</code> will override a value in
            column <code>value</code>.</td>
    </tr>

    <tr>
        <td>style</td>
        <td>string</td>
        <td>no</td>
        <td>Define the shape for the node.
            Choose from <code>rect</code> (default), <code>circle</code>,
            <code>database</code>, <code>image</code>, <code>text</code>,
            <code>dot</code>, <code>star</code>, <code>triangle</code>,
            <code>triangleDown</code>, and <code>square</code>.
            <br><br>

            In case of <code>image</code>, a column with name <code>image</code> must
            be provided, containing image urls.
            <br><br>

            The shapes <code>dot</code>, <code>star</code>, <code>triangle</code>,
            <code>triangleDown</code>, and <code>square</code>, are scalable.
            The size is determined by the columns <code>radius</code> or
            <code>value</code>.
            <br><br>

            When a column <code>text</code> is provided,
            this text will be displayed inside the shape in case of styles
            <code>rect</code>, <code>circle</code>, and <code>database</code>.
            For all other shapes, the text will be displayed right below the shape.

        </td>
    </tr>

    <tr>
        <td>text</td>
        <td>string</td>
        <td>no</td>
        <td>Text to be displayed in the node or under the image of the node.
            Multiple lines can be separated by a newline character <code>\n</code> .</td>
    </tr>

    <tr>
        <td>timestamp</td>
        <td>Date | Number</td>
        <td>no</td>
        <td>Timestamp used for filtering nodes when animating.
            See section <a href="#Animation">Animation</a> for more information.</td>
    </tr>

    <tr>
        <td>title</td>
        <td>string</td>
        <td>no</td>
        <td>Title to be displayed when the user hovers over the node.
            The title can contain HTML code.</td>
    </tr>

    <tr>
        <td>value</td>
        <td>number</td>
        <td>no</td>
        <td>A value for the node.
            The radius of the nodes will be scaled automatically from minimum to
            maximum value.
            Only applicable when the style of the node is <code>dot</code>.
            If a <code>radius</code> is provided for the node too, it will override the
            radius calculated from the value.</td>
    </tr>

    <tr>
        <td>x</td>
        <td>number</td>
        <td>no</td>
        <td>Horizontal position in pixels.
            The horizontal position of the node will be fixed.
            The vertical position y may remain undefined.</td>
    </tr>
    <tr>
        <td>y</td>
        <td>number</td>
        <td>no</td>
        <td>Vertical position in pixels.
            The vertical position of the node will be fixed.
            The horizontal position x may remain undefined.</td>
    </tr>

</table>


<h3>Links</h3>

<p>
    The table with links must at least contain columns <code>from</code> and
    <code>to</code>.
    The table can have extra columns, used to define the type and style of
    individual links. Values in optional columns can be left <code>undefined</code>
    for individual nodes. In that case, the default value will be applied.
</p>

<p>
    A Google DataTable with links is constructed as:
</p>

<pre class="prettyprint lang-js">
var linksTable = new google.visualization.DataTable();
linksTable.addColumn('number', 'from');
linksTable.addColumn('number', 'to');
// ... optionally add more columns

linksTable.addRow([1, 3]);
// ... more data
</pre>

<p>
    A JavaScript Array with links is constructed as:
</p>
<pre class="prettyprint lang-js">
var linksTable = [];

linksTable.addRow({
  'from': 1,
  'to': 3
});
// ... more data
</pre>

<p>
    The data columns are defined as:
</p>

<table>
    <tr>
        <th>Name</th>
        <th>Type</th>
        <th>Required</th>
        <th>Description</th>
    </tr>

    <tr>
        <td>action</td>
        <td>string</td>
        <td>no</td>
        <td>By specifying <code>action</code>, a link can be created, updated,
            or deleted. This is useful in combination with <code>timestamp</code>
            to animate history, or for dynamically updating the network.

            An action on a link can only be used when the link has an id.

            Available values are: <code>create</code> (default),
            <code>update</code>, or <code>delete</code>.

        </td>
    </tr>

    <tr>
        <td>altdashlength</td>
        <td>number</td>
        <td>no</td>
        <td>Length of the alternated dash in pixels on a dashed line.
            Specifying <code>altdashlength</code> allows for creating
            a dashed line with a dash-dot style, for example when
            <code>dashlength=10</code> and <code>altdashlength=5</code>.
            See also the option <code>dashlength</code>.
            Only applicable when the line style is <code>dash-line</code>.</td>
    </tr>

    <tr>
        <td>color</td>
        <td>string</td>
        <td>no</td>
        <td>A HTML color for the link.</td>
    </tr>

    <tr>
        <td>dashlength</td>
        <td>number</td>
        <td>no</td>
        <td>Length of a dash in pixels on a dashed line.
            Only applicable when the line style is <code>dash-line</code>.</td>
    </tr>

    <tr>
        <td>dashgap</td>
        <td>number</td>
        <td>no</td>
        <td>Length of a gap in pixels on a dashed line.
            Only applicable when the line style is <code>dash-line</code>.</td>
    </tr>

    <tr>
        <td>fontColor</td>
        <td>String</td>
        <td>"black"</td>
        <td>Font color for the text label of the link.
        Only applicable when "text" is defined.</td>
    </tr>

    <tr>
        <td>fontFace</td>
        <td>String</td>
        <td>"sans"</td>
        <td>Font face for the text label of the link,
            for example "verdana" or "arial".
            Only applicable when "text" is defined.</td>
    </tr>

    <tr>
        <td>fontSize</td>
        <td>Number</td>
        <td>14</td>
        <td>Font size in pixels for the text label of the link.
            Only applicable when "text" is defined.</td>
    </tr>

    <tr>
        <td>from</td>
        <td>*</td>
        <td>yes</td>
        <td>The id of a node where the link starts. The type must correspond with
            the type of the node id's. This is normally a number, but can be any
            type.</td>
    </tr>

    <tr>
        <td>length</td>
        <td>number</td>
        <td>no</td>
        <td>The length of the link in pixels.</td>
    </tr>

    <tr>
        <td>style</td>
        <td>string</td>
        <td>no</td>
        <td>Define a drawing style for the link.
            Choose from <code>line</code> (default), <code>arrow</code>,
            <code>arrow-end</code>, <code>moving-arrows</code>,
            or <code>dash-line</code>.
        </td>
    </tr>

    <tr>
        <td>text</td>
        <td>string</td>
        <td>no</td>
        <td>Text to be displayed halfway the link.</td>
    </tr>
    
    <tr>
        <td>textFrom</td>
        <td>string</td>
        <td>no</td>
        <td>Text to be displayed on the start of the link.</td>
    </tr>
    
    <tr>
        <td>textTo</td>
        <td>string</td>
        <td>no</td>
        <td>Text to be displayed on the end of the link.</td>
    </tr>

    <tr>
        <td>timestamp</td>
        <td>Date | Number</td>
        <td>no</td>
        <td>Timestamp used for filtering links when animating.
            See section <a href="#Animation">Animation</a> for more information.</td>
    </tr>

    <tr>
        <td>title</td>
        <td>string</td>
        <td>no</td>
        <td>Title to be displayed when the user hovers over the link.
            The title can contain HTML code.</td>
    </tr>

    <tr>
        <td>to</td>
        <td>*</td>
        <td>yes</td>
        <td>The id of a node where the link ends. The type must correspond with
            the type of the node id's. This is normally a number, but can be any
            type.</td>
    </tr>
    <tr>
        <td>value</td>
        <td>number</td>
        <td>no</td>
        <td>A value for the link.
            The width of the links will be scaled automatically from minimum to
            maximum value.
            If a <code>width</code> is provided for the link too, it will override the
            width calculated from the value.</td>
    </tr>

    <tr>
        <td>width</td>
        <td>number</td>
        <td>no</td>
        <td>Width of the line in pixels. The <code>width</code> will
            override a specified <code>value</code>, if a <code>value</code> is
            specified too.</td>
    </tr>
</table>



<h3>Packages</h3>
<p>
    The table with packages must at least contain columns <code>from</code> and
    <code>to</code>.
    The table can have extra columns, used to define the type and style of
    individual packages. Values in optional columns can be left <code>undefined</code>
    for individual nodes. In that case, the default value will be applied.
</p>

<p>
    There are two types of packages:
</p>

<ul>
    <li><b>Automatic</b>. When no value for the <code>progress</code> is provided,
        the package is automatically moved from start node to end node, and deleted
        once it has reached the end node. The duration can be customized by setting
        a value for <code>duration</code>.</li>
    <li><b>Manual</b>. When a value for the <code>progress</code> is provided,
        the package is positioned at the given progress between start and end node.
        The progress can be updated dynamically via the method <code>addPackages</code>,
        and can be deleted via the method <code>deletePackage</code>. Manual packages
        must have an id specified, in order to be able to update and delete them lateron.
</ul>

<p>
    A Google DataTable with automatically animated packages is constructed as:
</p>

<pre class="prettyprint lang-js">
var packagesTable = new google.visualization.DataTable();
packagesTable.addColumn('number', 'from');
packagesTable.addColumn('number', 'to');
// ... optionally add more columns

packagesTable.addRow([1, 3]);
// ... more data
</pre>

<p>
    A Google DataTable with manually animated packages is constructed as:
</p>

<pre class="prettyprint lang-js">
var packagesTable = new google.visualization.DataTable();
packagesTable.addColumn('number', 'id');
packagesTable.addColumn('number', 'from');
packagesTable.addColumn('number', 'to');
packagesTable.addColumn('number', 'progress');
// ... optionally add more columns

var id = 1;
var progress = 0.2;
packagesTable.addRow([id, 1, 3, progress]);
// ... more data
</pre>


<p>
    A JavaScript Array with packages is constructed as:
</p>
<pre class="prettyprint lang-js">
var packagesTable = [];

packagesTable.addRow({
  'from': 1,
  'to': 3
});
// ... more data
</pre>


<p>
    The data columns are defined as:
</p>

<table>
    <tr>
        <th>Name</th>
        <th>Type</th>
        <th>Required</th>
        <th>Description</th>
    </tr>

    <tr>
        <td>action</td>
        <td>string</td>
        <td>no</td>
        <td>By specifying <code>action</code>, a package can be created or deleted.

            Available values are: <code>create</code> (default),
            <code>update</code>, or <code>delete</code>.

            When a package is created with an id which already exists, the existing
            package will be updated. The <code>action</code> property can be used in
            combination with <code>timestamp</code> to animate history.
        </td>
    </tr>

    <tr>
        <td>color</td>
        <td>string</td>
        <td>no</td>
        <td>A HTML color for the package.</td>
    </tr>
    <tr>
        <td>duration</td>
        <td>number</td>
        <td>no</td>
        <td>Duration in seconds the animation of the package moving from start to
            end node. Only applicable when progress is not provided.
        </td>
    </tr>

    <tr>
        <td>from</td>
        <td>*</td>
        <td>yes</td>
        <td>The id of a node where the link starts. The type must correspond with
            the type of the node id's. This is normally a number, but can be any
            type.</td>
    </tr>

    <tr>
        <td>id</td>
        <td>*</td>
        <td>yes</td>
        <td>A unique id for the package. Packages cannot have duplicate id's.
            An id is required for packages with manually defined progress,
            in order to be able to update or delete them lateron.
        </td>
    </tr>
    <tr>
        <td>image</td>
        <td>string</td>
        <td>no</td>
        <td>Url of an image. Only applicable when style is <code>image</code>.</td>
    </tr>

    <tr>
        <td>progress</td>
        <td>number</td>
        <td>no</td>
        <td>A number between 0 and 1 which determines the progress of the package
            between the start and end node. If progress is defined, the package must
            also have an id defined.
        </td>
    </tr>

    <tr>
        <td>radius</td>
        <td>number</td>
        <td>no</td>
        <td>The radius of the package. Only applicable when style is <code>dot</code>.</td>
    </tr>

    <tr>
        <td>style</td>
        <td>string</td>
        <td>no</td>
        <td>Define a drawing style for the package.
            Choose from <code>dot</code> (default), <code>image</code>,
            <code>star</code>, <code>triangle</code>, <code>triangleDown</code>, or
            <code>square</code>.

            In case of an image, a column with image url must be provided in the table.
        </td>
    </tr>

    <tr>
        <td>title</td>
        <td>string</td>
        <td>no</td>
        <td>Title to be displayed when the user hovers over the package.
            The title can contain HTML code.</td>
    </tr>

    <tr>
        <td>to</td>
        <td>*</td>
        <td>yes</td>
        <td>The id of a node where the link ends. The type must correspond with
            the type of the node id's. This is normally a number, but can be any
            type.</td>
    </tr>

    <tr>
        <td>timestamp</td>
        <td>Date or number</td>
        <td>no</td>
        <td>The time on which this package is added or removed.
            Only applicable in combination with the column <code>action</code>.
            When timestamp is provided, a slider with start and stop button is created
            to enable playing history.
        </td>
    </tr>

    <tr>
        <td>value</td>
        <td>number</td>
        <td>no</td>
        <td>A value for the package.
            The radius of the packages will be scaled automatically from minimum to
            maximum value.
            Only applicable when the style of the node is <code>dot</code>.
            If a parameter <code>radius</code> is provided for the node too,
            this will override the radius calculated from the value.</td>
    </tr>

</table>

<h2><a name="Data_Import"></a>Data Import</h2>

<p>
    Network contains parser to import data in the
    <a href="http://en.wikipedia.org/wiki/DOT_language" target="_blank">DOT language</a>.
    There following methods are available:
</p>


<table>
<tr>
    <th>Method</th>
    <th>Return Type</th>
    <th>Description</th>
</tr>
<tr>
    <td>links.Network.util.parseDOT(data)</td>
    <td>Object</td>
    <td>
        Parse a string containing data in DOT language into a JSON object.
        The returned object contains two arrays, <code>nodes</code>,
        <code>edges</code>, containing the parsed nodes and edges.
    </td>
</tr>
    <tr>
        <td>links.Network.util.DOTToNetwork(data)</td>
        <td>Object</td>
        <td>
            Convert a string containing a graph in DOT language into a map
            containing with nodes and edges in the format of Network.
            The returned object contains parameters <code>nodes</code>,
            <code>edges</code>, and <code>options</code>, which can be used
            directly to draw a network using <code>draw(nodes, edges, options)</code>.
        </td>
    </tr>
</table>

<p>
Example usage:
</p>

<pre class="prettyprint lang-js">
    // create a network view
    var network = new links.Network(container);

    // parse data in DOT-notation
    var dot = 'digraph {1 -> 1 -> 2; 2 -> 3; 2 -- 4; 2 -> 1 }';
    data = links.Network.util.DOTToNetwork(dot);

    // draw the data
    network.draw(data.nodes, data.edges, data.options);
</pre>


<h2><a name="Configuration_Options"></a>Configuration Options</h2>

<p>
    Options can be used to customize the network. Options are defined as a JSON object.
    All options are optional.
</p>

<pre class="prettyprint lang-js">
var options = {
    'width':  '100%',
    'height': '400px',
    'links': {
        'color': 'red',
        'width': 2
    }
};
</pre>

<p>
    The following options are available.
</p>

<table>
<tr>
    <th>Name</th>
    <th>Type</th>
    <th>Default</th>
    <th>Description</th>
</tr>

<tr>
    <td>backgroundColor</td>
    <td>String or Object</td>
    <td>"white"</td>
    <td>The background color for the main area of the chart.
        Can be either a simple HTML color string, for example: 'red' or '#00cc00',
        or an object with optional properties stroke, strokeWidth, and fill.</td>
</tr>
<tr>
    <td>backgroundColor.stroke</td>
    <td>String</td>
    <td>"#666"</td>
    <td>The color of the chart border, as an HTML color string.</td>
</tr>
<tr>
    <td>backgroundColor.strokeWidth</td>
    <td>Number</td>
    <td>1</td>
    <td>The border width, in pixels.</td>
</tr>
<tr>
    <td>backgroundColor.fill</td>
    <td>String</td>
    <td>"white"</td>
    <td>The chart fill color, as an HTML color string.</td>
</tr>

<tr>
    <td>groups</td>
    <td>Object</td>
    <td>none</td>
    <td>It is possible to specify custom styles for groups.
        Each node assigned a group gets the specified style.
        See <a href="#Groups">Groups</a> for an overview of the available styles
        and an example.
    </td>
</tr>

<tr>
    <td>height</td>
    <td>String</td>
    <td>"400px"</td>
    <td>The height of the network in pixels or as a percentage.</td>
</tr>

<tr>
    <td>links.altdashlength</td>
    <td>number</td>
    <td>none</td>
    <td>Length of the alternated dash in pixels on a dashed line.
        Specifying <code>altdashlength</code> allows for creating
        a dashed line with a dash-dot style, for example when
        <code>dashlength=10</code> and <code>altdashlength=5</code>.
        See also the option <code>dashlength</code>.
        Only applicable when the line style is <code>dash-line</code>.</td>
</tr>

<tr>
    <td>links.color</td>
    <td>String</td>
    <td>"#2B7CE9"</td>
    <td>The default color of a link.</td>
</tr>

<tr>
    <td>links.dashlength</td>
    <td>number</td>
    <td>10</td>
    <td>Length of a dash in pixels on a dashed line.
        Only applicable when the line style is <code>dash-line</code>.</td>
</tr>

<tr>
    <td>links.dashgap</td>
    <td>number</td>
    <td>5</td>
    <td>Length of a gap in pixels on a dashed line.
        Only applicable when the line style is <code>dash-line</code>.</td>
</tr>

<tr>
    <td>links.length</td>
    <td>Number</td>
    <td>100</td>
    <td>The default length of a link.</td>
</tr>
<tr>
    <td>links.style</td>
    <td>String</td>
    <td>"line"</td>
    <td>The default style of a link.
        Choose from <code>line</code> (default), <code>arrow</code>,
        <code>moving-arrows</code>, <code>dash-line</code>.</td>
</tr>
<tr>
    <td>links.width</td>
    <td>Number</td>
    <td>1</td>
    <td>The default width of a link.</td>
</tr>

<tr>
    <td>nodes.borderColor</td>
    <td>String</td>
    <td>"#2B7CE9"</td>
    <td>Default border color of the nodes</td>
</tr>

<tr>
    <td>nodes.backgroundColor</td>
    <td>String</td>
    <td>"#97C2FC"</td>
    <td>Default background color of the nodes</td>
</tr>
<tr>
    <td>nodes.highlightColor</td>
    <td>String</td>
    <td>"#D2E5FF"</td>
    <td>Default background color of the node when the node is selected.</td>
</tr>

<tr>
    <td>nodes.fontColor</td>
    <td>String</td>
    <td>"black"</td>
    <td>Default font color for text in the nodes.</td>
</tr>
<tr>
    <td>nodes.fontFace</td>
    <td>String</td>
    <td>"sans"</td>
    <td>Default font face for text in the nodes, for example "verdana" or "arial".</td>
</tr>
<tr>
    <td>nodes.fontSize</td>
    <td>Number</td>
    <td>14</td>
    <td>Default font size in pixels for text in the nodes.</td>
</tr>
<tr>
    <td>nodes.group</td>
    <td>String</td>
    <td>none</td>
    <td>Default group for the nodes.</td>
</tr>
<tr>
    <td>nodes.image</td>
    <td>String</td>
    <td>none</td>
    <td>Default image url for the nodes. only applicable with style <code>image</code>.</td>
</tr>

<tr>
    <td>nodes.widthMin</td>
    <td>Number</td>
    <td>16</td>
    <td>The minimum width for a scaled image. Only applicable with style <code>image</code>.</td>
</tr>
<tr>
    <td>nodes.widthMax</td>
    <td>Number</td>
    <td>64</td>
    <td>The maximum width for a scaled image. Only applicable with style <code>image</code>.</td>
</tr>

<tr>
    <td>nodes.style</td>
    <td>String</td>
    <td>"rect"</td>
    <td>The default style for all nodes.
        Choose from <code>rect</code> (default), <code>circle</code>,
        <code>database</code>, <code>image</code>, <code>text</code>, <code>dot</code>.
        This style can be overridden by a group style, or by a style of an individual node.</td>
</tr>
<tr>
    <td>nodes.radius</td>
    <td>Number</td>
    <td>5</td>
    <td>The default radius for a node. Only applicable with style <code>dot</code>.</td>
</tr>
<tr>
    <td>nodes.radiusMin</td>
    <td>Number</td>
    <td>5</td>
    <td>The minimum radius for a scaled node. Only applicable with style <code>dot</code>.</td>
</tr>
<tr>
    <td>nodes.radiusMax</td>
    <td>Number</td>
    <td>20</td>
    <td>The maximum radius for a scaled node. Only applicable with style <code>dot</code>.</td>
</tr>

<tr>
    <td>packages.color</td>
    <td>String</td>
    <td>"#2B7CE9"</td>
    <td>Default color for all packages</td>
</tr>
<tr>
    <td>packages.duration</td>
    <td>Number</td>
    <td>1.0</td>
    <td>Default duration of animated packages in seconds.</td>
</tr>
<tr>
    <td>packages.image</td>
    <td>String</td>
    <td>none</td>
    <td>Default image for all packages.
        Style of the packages must be set to <code>image</code></td>
</tr>

<tr>
    <td>packages.widthMin</td>
    <td>Number</td>
    <td>16</td>
    <td>The minimum width for a scaled package. Only applicable with style <code>image</code>.</td>
</tr>
<tr>
    <td>packages.widthMax</td>
    <td>Number</td>
    <td>64</td>
    <td>The maximum width for a scaled package. Only applicable with style <code>image</code>.</td>
</tr>

<tr>
    <td>packages.radius</td>
    <td>Number</td>
    <td>5</td>
    <td>Default radius for all packages.</td>
</tr>
<tr>
    <td>packages.radiusMin</td>
    <td>Number</td>
    <td>5</td>
    <td>The minimum radius for a scaled package. Only applicable with style <code>dot</code>.</td>
</tr>
<tr>
    <td>packages.radiusMax</td>
    <td>Number</td>
    <td>20</td>
    <td>The maximum radius for a scaled package. Only applicable with style <code>dot</code>.</td>
</tr>

<tr>
    <td>packages.style</td>
    <td>String</td>
    <td>"dot"</td>
    <td>Default style for all packages.
        Choose from <code>dot</code> (default) or <code>image</code>.
        In case of an image, a column with image url must be provided in the table.</td>
</tr>

<tr>
    <td>selectable</td>
    <td>Boolean</td>
    <td>true</td>
    <td>If true, nodes in the network can be selected by clicking them, or
        by keeping the <code>Shift</code> key down and dragging a selection area around them.
        When the <code>Ctrl</code> key is down, the new selection is appended to the
        previous selection. If not, the new selection replaces the previous selection.</td>
</tr>

<tr>
    <td>stabilize</td>
    <td>Boolean</td>
    <td>true</td>
    <td>If true, the network is stabilized before displaying it. If false,
        the nodes move to a stabe position visibly in an animated way.</td>
</tr>

<tr>
    <td>width</td>
    <td>String</td>
    <td>"400px"</td>
    <td>The width of the network in pixels or as a percentage.</td>
</tr>

</table>

<br>

<h3><a name="Groups"></a>Groups</h3>

<p>It is possible to specify custom styles for groups of nodes.
    Each node having assigned to this group gets the specified style.
    The options <code>groups</code> is an object containing one or multiple groups,
    identified by a unique string, the groupname.
</p>
<p>
    A group can have the following styles:
</p>

<pre class="prettyprint lang-js">
var options = {
  // ...

  'groups': {
    'mygroup': {
      'style': 'circle',
      'borderColor': 'black',
      'backgroundColor': 'white',
      'fontColor': 'red',
      'fontSize': 18,
      'highlightColor': 'yellow'
    }
    // add more groups here
  }
};

var nodesTable = new google.visualization.DataTable();
nodesTable.addColumn('number', 'id');
nodesTable.addColumn('string', 'text');
nodesTable.addColumn('string', 'group');
// ... optionally add more columns

nodesTable.addRow([1, 'Node 1', undefined]); // will get the default style
nodesTable.addRow([2, 'Node 2', 'mygroup']); // will get the style from 'mygroup'
// ... more data
</pre>


<p>The following styles are available for groups:</p>
<table>
    <tr>
        <th>Name</th>
        <th>Type</th>
        <th>Default</th>
        <th>Description</th>
    </tr>

    <tr>
        <td>borderColor</td>
        <td>String</td>
        <td>"#2B7CE9"</td>
        <td>Border color of the node</td>
    </tr>

    <tr>
        <td>backgroundColor</td>
        <td>String</td>
        <td>"#97C2FC"</td>
        <td>Background color of the node</td>
    </tr>
    <tr>
        <td>highlightColor</td>
        <td>String</td>
        <td>"#D2E5FF"</td>
        <td>Background color of the node when the node is selected.</td>
    </tr>
    <tr>
        <td>image</td>
        <td>String</td>
        <td>none</td>
        <td>Default image for the nodes. Only applicable in combination with
            style <code>image</code>.</td>
    </tr>

    <tr>
        <td>fontColor</td>
        <td>String</td>
        <td>"black"</td>
        <td>Font color of the node.</td>
    </tr>
    <tr>
        <td>fontFace</td>
        <td>String</td>
        <td>"sans"</td>
        <td>Font name of the node, for example "verdana" or "arial".</td>
    </tr>
    <tr>
        <td>fontSize</td>
        <td>Number</td>
        <td>14</td>
        <td>Font size for the node in pixels.</td>
    </tr>
    <tr>
        <td>style</td>
        <td>String</td>
        <td>"rect"</td>
        <td>Choose from <code>rect</code> (default), <code>circle</code>,
            <code>database</code>, <code>image</code>, <code>text</code>,
            <code>dot</code>.
            In case of image, a column with name image must be provided, containing
            image urls.</td>
    </tr>
    <tr>
        <td>radius</td>
        <td>Number</td>
        <td>5</td>
        <td>Default radius for the node. Only applicable in combination with
            styles <code>rect</code> and <code>dot</code>.</td>
    </tr>

</table>



<h2><a name="Dynamic_Data"></a>Dynamic Data</h2>

<p>
    The Network is normally rendered using the method <code>draw</code>.
    The network can handle dynamic data in two ways:
</p>
<ul>
    <li>
        <b>Animation</b>
        A set with historical data can be animated over time.
    </li>
    <li>
        <b>Changeset</b>
        A drawn Network can be updated by appending a changeset to the Network.
    </li>
</ul>


<h3><a name="Animation"></a>Animation</h3>
<p>
    Historical data can be animated over time.
    To create an animation, the data sets with nodes, links, and
    packages must have a property <code>timestamp</code>,
    and has a property <code>action</code> describing the
    <a href="#Changeset">change</a> (create, update, or delete).
    The Network will automatically create an animation which runs from
    the earliest to the latest encountered timestamp.
    When the Network is rendered at a certain timestamp,
    all elements with a timestamp older than the current time will be rendered,
    and all elements without a timestamp.
</p>

<p>
    The animation state and speed can be manipulated using methods
    <code>animationSetAcceleration</code>,
    <code>animationSetDuration</code>,
    <code>animationSetFramerate</code>,
    <code>animationStart</code>,
    and <code>animationStop</code>.
</p>

<p>
    The following package table shows how to change the state of a package over time:
</p>

<pre class="prettyprint lang-js">
var packageTable = new google.visualization.DataTable();
packageTable.addColumn('number', 'id');
packageTable.addColumn('number', 'from');
packageTable.addColumn('number', 'to');
packageTable.addColumn('string', 'action');
packageTable.addColumn('string', 'title');
packageTable.addColumn('number', 'progress');
packageTable.addColumn('datetime', 'timestamp');

// package with id 7 moved over time from node 1 to node 2
//                   id, from, to, action,  title,              progress,  timestamp
packageTable.addRow([7,  1,    2, 'create', 'Copy data [0%]',   0.00,      new Date(2012,6,4,14,0,0)]);
packageTable.addRow([7,  1,    2, 'update', 'Copy data [10%]',  0.10,      new Date(2012,6,4,14,10,0)]);
packageTable.addRow([7,  1,    2, 'update', 'Copy data [20%]',  0.20,      new Date(2012,6,4,14,15,0)]);
packageTable.addRow([7,  1,    2, 'update', 'Copy data [50%]',  0.50,      new Date(2012,6,4,14,20,0)]);
packageTable.addRow([7,  1,    2, 'update', 'Copy data [80%]',  0.80,      new Date(2012,6,4,14,30,0)]);
packageTable.addRow([7,  1,    2, 'update', 'Copy data [100%]', 1.00,      new Date(2012,6,4,14,35,0)]);
packageTable.addRow([7,  1,    2, 'delete', undefined,          undefined, new Date(2012,6,4,14,40,0)]);
</pre>

<h3><a name="Changeset"></a>Changeset</h3>
<p>
    The data of a rendered Network can be changed dynamically.
    Data can be updated by appending a changeset to the Network
    using methods <code>addNodes</code>, <code>addLinks</code>, and <code>addPackages</code>.

    The appended data can contain new nodes, links, and packages, but can
    also adjust existing elements.
    For example, the title of a Node or the width of a link can be updated.
</p>

<p>
    The changeset is a regular DataTable like used
    The <code>action</code> property describes one of the following changes
</p>
<ul>
    <li>
        <b>create</b> Create an element (node, link, or package).
        When the new element has an id which already exists, the existing
        element will be overwritten.
    </li>
    <li>
        <b>update</b> Update an element, create when not existing.
        Only applicable when the element has an id.
    </li>
    <li>
        <b>delete</b> Delete an existing element.
        Only applicable when
    </li>
</ul>



<h2><a name="Methods"></a>Methods</h2>
<p>
    Network supports the following methods.
</p>

<table>
    <tr>
        <th>Method</th>
        <th>Return Type</th>
        <th>Description</th>
    </tr>

    <tr>
        <td>addLinks(links)</td>
        <td>none</td>
        <td>Dynamically appends links to the network.
            Parameter links contains a DataTable or Array.
            A link can be created, updated, or deleted by specifying the column
            <code>action</code> and choose a value <code>create</code>,
            <code>update</code>, or <code>delete</code>.
        </td>
    </tr>

    <tr>
        <td>addNodes(nodes)</td>
        <td>none</td>
        <td>Dynamically adds nodes to the network.
            Parameter nodes contains a DataTable or Array.
            A node can be created, updated, or deleted by specifying the column
            <code>action</code> and choose a value <code>create</code>,
            <code>update</code>, or <code>delete</code>.
    </tr>

    <tr>
        <td>addPackages(packages)</td>
        <td>none</td>
        <td>Dynamically appends packages to the network.
            Parameter packages contains a DataTable or Array.
            A package can be created, updated, or deleted by specifying the column
            <code>action</code> and choose a value <code>create</code>,
            <code>update</code>, or <code>delete</code>.
        </td>
    </tr>

    <tr>
        <td>animationSetAcceleration(acceleration)</td>
        <td>none</td>
        <td>Set the time acceleration for animation of history.
            Only applicable when packages with a timestamp are available.
            When acceleration is 1, history is played in real time.
            And for example acceleration of 10 will play history then times the speed of
            real time.</td>
    </tr>
    <tr>
        <td>animationSetDuration(duration)</td>
        <td>none</td>
        <td>Duration of the animation in seconds.
            Only applicable when packages with a timestamp are available.
            The animation speed is scaled such that the total duration of playing the
            history equals the set duration.</td>
    </tr>
    <tr>
        <td>animationSetFramerate(framerate)</td>
        <td>none</td>
        <td>Set the framerate in frames per second for animation of history.
            Only applicable when packages with a timestamp are available.
        </td>
    </tr>
    <tr>
        <td>animationStart()</td>
        <td>none</td>
        <td>Start animation of history.
            Only applicable when packages with a timestamp are available.
        </td>
    </tr>
    <tr>
        <td>animationStop()</td>
        <td>none</td>
        <td>Stop animation of history.
            Only applicable when packages with a timestamp are available.
        </td>
    </tr>

    <tr>
        <td>draw(nodes, links, packages, options)</td>
        <td>none</td>
        <td>Loads data, sets the provided options, and draws the network.
            Parameters nodes, links, and packages are a DataTable,
            and options is a name-value map in the JSON format.
            Both links and packages are optional and can be left undefined.
        </td>
    </tr>

    <tr>
        <td>getSelection()</td>
        <td>Array of selection elements</td>
        <td>Standard <code>getSelection()</code> implementation.
            Returns an array with one or multiple selections. Each selection contains
            the property <code>row</code>. The selections are not ordered.
        </td>
    </tr>

    <tr>
        <td>redraw()</td>
        <td>none</td>
        <td>Redraw the network. Useful after the camera position is changed externally,
            when data is changed, or when the layout of the webpage changed.</td>
    </tr>

    <tr>
        <td>setSelection(selection)</td>
        <td>none</td>
        <td>Standard <code>setSelection(selection)</code> implementation.
            <code>selection</code> is an array with selection elements. The visualization
            accepts one or multiple selection elements, which must have the property <code>row</code>.
            Example usage: <code>network.setSelection([{"row": 3}]);</code>.
        </td>
    </tr>

    <tr>
        <td>setSize(width, height)</td>
        <td>none</td>
        <td>Parameters <code>width</code> and <code>height</code> are strings,
            containing a new size for the visualization. Size can be provided in pixels
            or in percentages.</td>
    </tr>

    <tr>
        <td>start()</td>
        <td>none</td>
        <td>Start animation.
            Only applicable when there are animated links or nodes,
            or when the nodes are not yet moved to a stable position.</td>
    </tr>

    <tr>
        <td>stop()</td>
        <td>none</td>
        <td>Stop animation.
            Only applicable when there are animated links or nodes.</td>
    </tr>

</table>

<h2><a name="Events"></a>Events</h2>
<p>
    Network fires events after one or multiple nodes are selected.
    The event can be catched by creating a listener.
    Listeners can be registered using the event messages from the Google API or
    event messages from the CHAP Links library.
</p>

<p>
    Here an example on how to catch a <code>select</code> event.
</p>

<pre class="prettyprint lang-js">
function onselect() {
  var sel = network.getSelection();

  var info = 'selected row(s): ';
  for (var i = 0; i &lt; sel.length; i++) {
    info += sel[i].row + ' ';
  }

  alert(info);
}

google.visualization.events.addListener(network, 'select', onselect);
// Or, when not using the Google API:
//   links.events.addListener(network, 'select', onselect);
</pre>

<!-- TODO: document all events -->

<p>
    The following events are available.
</p>

<table>
    <col width="10%">
    <col width="60%">
    <col width="30%">

    <tr>
        <th>name</th>
        <th>Description</th>
        <th>Properties</th>
    </tr>

    <tr>
        <td>select</td>
        <td>Fired after the user selects or unselects a node by clicking it,
            or when selecting a number of nodes by dragging a selection area
            around them. Not fired when the method <code>setSelection</code>
            is executed. The corresponding rows in the data table are selected.
            <br>
            The selected rows can be retrieved via the method <code>getSelection</code>.
        </td>
        <td>none</td>
    </tr>

    <tr>
        <td>ready</td>
        <td>The network is loaded and ready for external method calls.
            If you want to interact with the network, and call methods after you draw it,
            you should set up a listener for this event before you call the draw method,
            and call them only after the event was fired.</td>
        <td>none</td>
    </tr>
</table>


<h2><a name="Data_Policy"></a>Data Policy</h2>
<p>
    All code and data are processed and rendered in the browser. No data is sent to any server.
</p>

</div>
</body>
</html>
